Jorge Montanez breaks down the last week in saves and middle relievers on the rise in the latest closer report.

Carlos Narvaez was the Red Sox’s cleanup hitter for Friday night’s series opener in the Bronx — his first trip there since the Yankees traded him to Boston in December.

Headed to the injured list is right-handed relief pitcher Luke Weaver, who tweaked his hamstring while warming up in the bullpen on Sunday and was unable to pitch. Weaver was diagnosed with a left hamstring strain and is expected to miss four to six weeks of action.

The Yankees officially shifted Luke Weaver to the 15-day injured list for a hamstring strain that will require longer than those 15 days.

Aaron Boone didn’t sound overly optimistic late Sunday while discussing Luke Weaver, who had to cut his warmup short in the bullpen before the ninth inning of that night’s game at Dodger Stadium because he “felt something” in his left hamstring. Boone’s fears were soon confirmed.

PRP treatment gives Yankees pitcher hope for early return originally appeared on Athlon Sports. Yankees closer Luke Weaver is showing encouraging signs early in his recovery from a left hamstring strain. After receiving a PRP injection this week, Weaver resumed throwing Thursday and again before Friday’s series opener against the Red Sox.

On this version of the Yankees, you might be able to make a case that Weaver was the fourth-most important player. Such was the serenity/effectiveness that he brought to a pressure-packed job

After losing franchise ace Gerrit Cole for the season and marching on without Luis Gil or Giancarlo Stanton able to make their debuts so far, the Yankees have now lost their most trusted bullpen arm as Luke Weaver heads to the injured list with a hamstring ailment.